Since the 1920s, Hitler had greatly admired Italian dictator Benito Mussolini both personally and politically, and he considered Fascist Italy a natural ally for the German Reich. At first, however, Mussolini was hostile to the Nazi regime. He had no sympathy for Nazi racial theories and mistrusted Hitler's expansionist intentions, especially with regard to Austria and South Tyrol, which had belonged to Italy since 1919. Up until 1935, Mussolini repeatedly protested both German rearmament and the country’s aggressive foreign policy, and rejected all of Hitler's attempts at diplomatic rapprochement. The German-Italian relationship first changed with the Italian attack on Abyssinia in October 1935, after which the League of Nations imposed economic sanctions on Italy and isolated the country diplomatically. By remaining neutral in this matter, Hitler secured Mussolini's gratitude and laid the foundations for the later "Berlin-Rome Axis." Their common intervention on behalf of Franco in the Spanish Civil War put the final seal on Mussolini's decision to ally himself with Hitler against the Western powers. In 1937, Italy left the League of Nations and joined the German-Japanese "Anti-Comintern Pact." The German-Italian rapprochement reached its highpoint with the signing of the "Pact of Steel" on May 22, 1939, in which both sides committed themselves to mutual military and economic support in the event of a war of aggression.